Workpiece-holding pruning shears with resilient in-drawing gripper element



Dec. 25, 1956 v E. P. soRENsEN 2,775,032

WORKPIECE-HOLDING PRUNING SHEIARS WITH RESILIENT IN-DRAWING GRIPPER ELEMENT Filed oct. 19, 195s 5 Sheets-Sheet 1 DeC- 25, 1956 E. P. soRENsEN 2,775,032

woRKPIEcE-HOLDING PEUNING sHEARs WITH RESILIENT 11e-DRAWING GEIPPER ELEMENT Filed oct. 19, 1953 s sheets-sneer 2 \Q MQW NME EN NW De 25, 1956 E. P. soRENsEN woRxPIEcE-HOLDING PRUNING sHEARs WITH RESILIENT IN-DRAWING GRIPPER ELEMENT 3 Sheets-Sheet 3 Enea oct. 19, 1953 ,.solong as-:the implement jaws; .are `rheld closedgdurmglthe -woRKPIEcE-HoLDING PRUNING, when f RESILIENT lN-DRAWING GRIPPER ELEMENT Edgar P, Sorensen, ontario, caiif. `Application october 19,19s3se1ia1 N0.,386,'7,23 4 Claims. (ci. en -134) The invention relates to pruning shears and has particular reference to the type of shears which areepr'o- .vided with means to seize and maintain a rm supporting grip on the severed part of a treebran'ch, bush, vinegor plant ,being pruned so that thejsaidp'art, o r .workpiece vas it -will be termed hereinafter for the sake of brevity, maybe carefully deposited in arrec'eptacle or neat pile without being touched by either hand.

'Pruning shears of this kind are peculiarly suitable for use incutting oi bunches of `grapes or the blooms zof oweringvplants which are very fragile and otherwise would be dropped andinjured whenever the p ikers irnplement-freehand is engaged in steadying the vvine for vplant lthat bears thepart being severed, and thuscannot be used tograspthe latter.

Numerous types of workpiece-holdingpruning`sh ars are available onthe market, but are deficient in respects. For instance, the workpiece-contacting faoesof the gripping .elements associated -vvithzthe 'Cutting iaw'fs ASi the shears generallyV are arranged parallel `-tothe.' workpiece-engaging edges Orffaes Ofsaildiaws- This ar r'ne'nt is unfortunatebe,causeas is wel own,.the,cu ing j aws present an outwardly diverging' mentof Itheir workpiece-contacting ejdg'es o vfac'z'es th'r'o`u`g`hout. closing m'over`n'ent .of Y the jaws. jlConseQu ,thegbranch, vine, or' the like, being` pruned, be lin the mouth er the Acutting jaw's by.. the i rr`i "llarid,"therelwill. be a strongtendencybfa 'fXPel th branch, etc.thro1f1.ah. nincihfna.r.sduee2 gatio'n, 4.particularly when ythelatte'r i'slhard, roundand slippery. :With rthe workpiece-contacting vfaces of the 'grippingelements arranged parallel tojf'he4 ,CQrresp'onding faces' or edges ofthe cutting jawsfthf'er intended'fln f thegripping elernents iscountera'cted by` theywlorkp eX'plli g action tif-.the cutting jawsV in acne-hand, p attempt.

:with nrelfor'esing d :.J'ee-lldig -liliigh Y ).ebjeetir provide an; improved workpiece,- gfr aftaehment to existing, pruning; shea corporation f in the implement structure, at s *.fnniifacture, K.which 4device .includesqalliiXed grippeij el e Vnier-.tecn onefyi'rnplement-jaw and a, resiliently compressible gripperekment Von.`tl1ej3-therjaw..tliatrtcoaizts ,with yaid liked. g'r'ip r .element in suchl ani'anner thatg VV'IKP e* alSt Ille., TESilntlysclipSbl@i I. as it is- .being f severed ,willi .compress .the latter, elementfto ,'cfieate a4 temporaryrestraining'.wall on the outer side-.of .the'Vor-kpiece, i. e inthedirectiongofrthe vmouth lie endwise eXpfulsionrfrom. .betweenthe implement jaWS due to..thein normal ,squeezing .faction as they closepn the workpiece `with their. relatively- .inclinedcutting`- s. ,Mreover' the worlfipiecefy will ,continuato ,b wal .,act:.of. disposing .of saidworkpiece, A. Y ron is ter-use. rubber, or any i ,-Anotherobject of the inven represented workpiece at thestage immediately preceding 2,775,032 'atented Dec. 2 5, i956 suitable-substancepossessing the saine elastic properties accidental ejection of the latter from between the implement jaws.

rvA further Aobject is to provide a resiliently compressiblegr'ipper element of such composition and construction thatit'will exert an in-drawing force, or pull, on the workpiece inaddition to barring egress only passively.

Other objects, advantages and features of the invention Vwill become apparent as the following specific descrip- Ation is read in connection with the accompanying draw- Fig; lisa side elevationalview of a pair of pruning shears of well-,known make which has been modernized to include the improved workpiece-holding adjunct, kshowing the jawsofv the implement closing on a conventionally cuttih'gjactiomFig'. 2 is a similar View, partially broken ewan-'showing the nal stage after the workpiece has been completely severed; Fig. 3 is a cross-section yon line 3--3 "oftFig 1; Fig'. 4 is a similar view online 1T- tof Fig. 1; vand Fig. l5 is afront elevation of a modiedanvil jaw lia'ving thexed gripperelement formed integral therewith.

"Fig, 6 is a detail sideelevation of a modilied form of the resiliently compressiblegripper element; Fig. 7visL a 'rear elevation ofthe s ame; and Fig. Slis'a bottom yplan view ,thereof.

v 9 is a fragmentary side ,elevation of the cutting jaw of apair of pruning shears having a still further modi- "iied form' of resiliently compressib'le gripper element, ap- `1; lied t hereto; 'Fig..9a is a view similar to Fig. 2 showing tliemodied resilient gripper element inthe final gripping tage; and Fig. 10 is a cross-section on line 10--10 of :.,g'..9'

"Fig. 11 is a sidev elevation of -a modication of .the

vrfesiliently cornpressible gripper element shown in Figs. 9

a nd 10. Eig', 1 2 is a detaillfragmentary sidevelevation of the cutt1ng' jaw of the type of pruning shears adopted for purposes of illustration which has `been modified to improve lthe mode of attachment of the resiliently compressible gripperelernent; Fig. 13A is a similar view. showing a correspondingly simplied resilientlycompressible gripper .e le"rnent inassembled condition on the modified jaw; and V14,is a front elevation of theassembly shown in lig. .13.

Fig'. 15 is a fragmentary side elevation of a. `pairof g priming shears having a still further modiedformof resiliently compressible gripper element in assembled condition, shofwing the jaws of theimplementA closing on a conventionally represented workpiece at a stage immediat'ely4 preceding cutting action; Fig. 16 is a similar view showing the final stage after the workpiece has been completelysvevered; and Fig. .17 is a cross-section on line f11f-11efLFig. 15.

Fig. 1S is al sectional view't-aken ont-he line-18-18of rig. 2.

Referring now in detail tothe drawings, inwhichlike referencecharacters-designate corresponding parts in the several views, the improved workpiece-holding invention liarsbeendisclosed in a few presently contemplatedembodiments wherein it is structurally adapted .to iit a pair .ofpruningshears of. well-known make ychosen for the .purpose ofillustrationonly. l Obviously, it is wellwithin Pruning Shel's designs.-

.the scope .,of the invention to adapt-the same to other Ilie implementv disclosed. in. the drawings ,has relatively movable handles A and B that are connected together by transverse pivot pin C. At this juncture, it may be explained that the term handle is used in the trade to embrace both the rearwardly extending manipulating portion and the short shank portion immediately in advance of the pivot to which -a workpiece-engaging jaw is added either as an integral part or by attachment, as by rivets or bolts. In the illustrative example, handle A has a cutting jaw D removably secured to its shank portion. The said jaw D is in the form of a V-type blade having a straight inner cutting edge d and a smoothly curved longitudinally convex outer margin d which is blunt through- `out the greater part of its `length and merges with cutting edge d at the forward end of the jaw in a conveniently sharp nose d". Whereas some types of pruning shears have cutting blades on both jaws that overlap as they close, the implement chosen for the purpose of illustration is of that type which employs an anvil of comparatively soft metal lon one jaw for engagement by a cutting blade on the other jaw. Therefore, in this example handle B is represented as having an anvil j-aw E that conforms in profile to cutting jaw D. The lstraight and laterally at inner anvil face e of jaw E is arranged to bear flatly and evenly against the 4opposed edge d of cutting jaw D when both jaws are complete-ly closed.

In accordance with the present invention, a rigid gripper element 20 is -aixed to one jaw of the pruning shears implement `and a resiliently compressible gripper element 21 is mounted on the other jaw in opposed coacting relation to rigid gripper element 20. If the shears were of the type in which both jaws have cutting blades, it would not matter which element is borne by which jaw. However, in the illustra-tive example, wherein one jaw is a. cutting blade and the other has an anvil face for coaction with said cutting blade, it is preferred to aiiix the rigid gripper element Ztl to anvil jaw E and to mount the resiliently compressible gripper element 21 `on cutting jaw D either directly or in such a manner 4that it moves with said jaw D in close side-by-side proximity.

For the sake of brevity, the resiliently compressible gripper element will from now on be termed the resilient gripper element.

Rigid gripper element 20 Will be described in detail iirst. As shown particularly in Fig. 4, `said element 20 is preferably cut from a metal bar of L-shaped crosssection to provide an attaching ange 22 and a perpendicular ange 23 which presents an inner workpiececontact face 24 in coacting opposition to the corresponding face of the resilient gripper element, which will be described in detail presenting. The forward edge of attaching ange 22 is rounded in conformity to the 'shape of anvil jaw E. Rigid gripper element 20 is assembled with anvil jaw E in a position wherein workpiece-contact face 24 is slightly offset outwardly from anvil face e in order that the rigid gripper element will not be subjected unnecessarily to the strong cutting force exerted by cu-tting jaw D on anvil jaw E. Rigid gripper element 20 should be applied to the side jaw E that is best suited to the handedness characteristics of prospective buyers. For example, if a particular implement is to be `adapted for use by right-handed persons, both gripper elements should be applied to the right side, because it is custom-ary to employ the left hand to steady the branch, vine, etc., so that the workpiece will project from the right side of the implement jaws. When the improved workpieceholding invention is built into pruning shears at the time of manufacture, it will be the practice, of course, to produce both right-hand and left-hand implements in respective numbers proportionate to the percentages yof persons who may require the use of pruning shears that are likely to be right-handed and left-handed. The implement depicted in the accompanying drawings is intended to be held in `the hand with the anvil jaw located underneath the cutting jaw. In this position, some of the weight ofworkpiece W will be sustained by anvil face e of jaw E so it is preferred to aix rigid gripper element 20 to this particular jaw in order that resilient gripper element 21 will not be subjected to excessive weight.

Any suitable means may be employed to attach ange 22 of rigid gripper element 20 to anvil jaw E, but a simple expedient in modification of an existing implement is to drill registering holes through said ange and jaw for penetration by attaching bolts 25, or equivalent attaching means. In accordance with the contemplated merchandising practice, packaged sets of mated gripper elements and the attaching and mounting means therefor will be supplied for use by consumers who may desire to modernize pruning shears already in possession. The attaching flange of the rigid gripper element of such a set Will therefore be pre-drilled and thus may be used as a template in drilling registering holes in the anvil jaw of the implement to which said gripper element is to be aixed. The same practice applies to the resilient gripper element and its mounting means, which will become more clearly understood as the description progresses.

Fig. 5 illustrates the alternative manner in which the anvil jaw of -a pair of pruning shears may be provided with a rigid gripper element coincident with manufacture of the implement. In this instance, rigid gripper element 20 may be formed by an integral lateral flange e' on anvil jaw E. In this same gure, ange e is shown as being faced with rubber, which may be desirable when lthe implement is to be used almost exclusively for cutting smalldiameter workpieces, such as the stems of grape bunches and flowers. However, it is preferred to have a hard, smooth workpiece-contact face 24 when the implement is to be used mostly in cutting large-diameter, round, hard workpieces in order that minimum resistance will be oered to the in-drawing elect of resilient gripper element 21, particularly the highly eiective embodiments disclosed in Figs. 6, 7, 8, 11, 15 and 16, as will be explained more fully later herein.

For home modification of pruning shears, it is preferred to provide a cantilever mount for the resilient gripper element 21 instead of applying it directly to cutting jaw D. The structure of any selected mounting means will depend upon the form of the resilient gripper means, so the latter will be described in detail first. The resilient gripper element 21 shown in Figs. 1, 2 and 3 is in the form of a narrow block of rubber, or equivalent material, of suitable softness. In prole, the rubber block is a general quadrilateral, but the principal reason for this configuration is to approximate the area and general shape of cutting jaw D without resorting to any curved marginal faces. The really important thing to be accomplished is to give resilient gripper element 21 a form and location in relation to cutting jaw D that will insure registration 0f the inner, or bottom, work-piece-contact face 26 of said element with the corresponding face 24 of rigid gripper element 20 when the implement jaws are closed, and which will cause said face 26 of resilient gripper element 21 to be angularly arranged with respect to cutting edge d of jaw D when both jaws are open in a manner which makes the nose portion 27 of said element 21 project inward from nose d" of jaw D. By this arrangement of the nose portion 27 of resilient gripper element 21, an inclined restraining wall of restricted vertical extent is permanently provided on said element at the mouth of the space between jaws D and E to function in a manner to be described presently. For registration of workpiece-contact faces 24 and 26 of the respective gripper elements 20 and 21, it is, of course, necessary to mount resilient gripper element 21 at the right side of cutting jaw D. The previously mentioned cantilever mounting means for this purpose comprises an elongated, bent mounting member 28 which preferably is stamped from sheet metal. A perpendicular stiiening flange 29 is formed along the upper edge of mounting member 28 from the front end thereof rearward to a point in rear of its center. Flange 29 projects toward the right and the portion thereof in advance of the bend in mounting member 28 overlies resilient vglpl'l' @lement 21 in contact with the upper thick edge e-inamgoee of said `element-and :thusfseryes-:asfbackingf menslljtherefr f-.in-.additiontto itsfstieningetunction fonmounting member -28;-as fa: awhole. xAt :substantially its; midpoint-mounting ,member .28 is f drilledgforv` engagement by; pivot pin 'C `of 1 handles lA: andnfB, whereby :member .-28 @is held :in bearing contact with the right side face ofyhandle B. At -a sufficient distance in-rear. ofpivot pin-jC-;to` avoid interference withV` pivotal l movement of handle `B, :tmounting ,member28 is -oiset-inwardly tofbring ,its-rear armfinto rilat. eontact-withhandle A. Here, thezextremity-of said -rear arm is ianchoredto handle-A in any convenient manner, as by screw i30forequiyalent means. Resilient gripper element 21 is secured in position against theright side face ofthe-front, `downwardly h entarmioftmounting f'member .28 and inabutting contact with rbackingange 429 by suitable means, such asthe ,clamping cleat 31 and `screws 32 ywhich fare preferred .f for convenience. in replac- .ving the rubber gripper-elementwhen worn orfvdamage'd.

The :operation of lthemodernized pruning 'shears disnclosed in-'Fi'gs l-to-4, inclusive,-fwillfnow be described. Referring first to-F ig. l,it will be-observedthat, :when Athefirnplement jaws AD-E are ,closed `onwworkpiece -W ...untiLthe latter is contactedvbythe-respective faces Z4-and 2,6 of rigid lgripper-.element l2() and resilient gripper element 21, as-shownin solid lines, vthe-said:faceswill be ,substantiallyrparallel due tothe normaldnclination of face. 26,` in relation to cutting edge dof jaw D. Therefore, duringcontinued closingof the implementjaws into the t-relation represented in broken lines, the lgripper `elements ,20--21..will exert nov expelling force onworkpiece lOn the contrary, duringf-thisjaw movement,-workpie,ce vW will-indent resiliently compressible, gripper element21. The-resultof fthis indentation will be suchv deformation .of said element-21 that itsfnoseportion 27 will bulgefinwardlyy toward the nose of rigid, .gripperl element S2010 Vform a restraining lwall 33 fat theforward side of workpiece W, which also will have the effect of squeezing said workpiece inward or rearward, that is, toward the pivot pin C in sliding-.contact withanvil face eyofgjaw E. In a general sense,kthis will.bean-in-drawingeffect. Thereafter, in use of the resilient gripper element embodiment 'disclosedn Figs. l-to 4, the principal veffect of closing jaws D and E further-will-be to embedworkpiecefW-more and more deeply-inthe rubber massof -said element until vthe condition of Amaximum-confinement shown-intEig. 2 `is attained. It should bev apparent that the inclined opposed faces of implement jaws D-E-will be defeated in their normal tendency toeXpel-the workpiece, wherefore itis entirely practicable with my improved workpieceholding; device to render the pruning shears implement capableA of use in a one-'handed pruningoperation. That is, the implement will be manipulated-by one hand While the other will be free to hold a basket or other receptacle into which the severed workpieces may be deposited without being touched by either hand.

In Figs. 6 to 8, there is disclosed a modied form of resilient gripper element, which is intended to increase both the walling-in of the workpiece and the in-drawing effect on the same. In this instance, rubber or the like is used in the composition of resilient gripper element 21 the same as in the embodiment shown in Figs. l to 4. The rubber block is rectangular in profile but its lower edge portion has a shape that renders it comparatively stiff at the front nose-forming area and increasingly more soft and yieldable from there to the rear end of the block. While this rearward weakening or softening of the block may be achieved in other ways not shown, a simple and effective way is to cut away the lower edge at one side obliquely as at 34 to taper the bottom workpiece-contact face 26 from front to rear. Face 26 need not be tapered to a point, so the width of said face will at no place be so narrow as to objectionably weaken resilient gripper element 21. In fact only slight rearward gradation in relative yieldability is necessary to accomplishment of the desired purpose, which is to wall-in an engaged workpiece and to exert the additional in-drawing force on it. It

ishouldi be readily understood;withoutfurther. illustration 1 vthat-ase ai. workpiecegisfyengaged fby the Outer portion tof contact .face 26 inwardly; of ythe `.comparatively stii noseforming .-area, `'the lweakerareas fofT face k261will tend to yield andipermitthe workpiece toy drift withagra'dually' increasing -speedy ,frearwa'rdlyffinto the, mouthof; the A'implement; jawsfdue to the progressive rearward declinationeof resistance to compression.

I Eigs.-9 Yand l0disclose another modified form ,oftrubvberf'gripperelementi: 21 :that is `adapted to fitv Athepmounting member 28 represented in Figs. 1 4to 4. Instead offusing a solid block ofrubberfelement 21 .isy produced yby' folding-ax ;s,uitable;fnumber (three-in this instance) ;of sheets fof rubber, such ;as;may 'be cut -from discarded automobile inner tubing,-of-twiceythe normal-width of .said-:element intothe requiredcompacttlaminated form composed of outer, intermediate andinnerplies 35, 35a:and.35b',v=;re

,spectively. After rthe ,said plies, or Y laminae, are stitched `togetherdalonga; medial line,- asl at 36,- the-:cut-longitudiinalfedge-portion `-ofelement 21 is vdrilled toumatch `the screwholes ,in mounting-member 28 and said. element; is

4clampedtherein. in ithe vusual manner previously Jdescribed. .'Ftig. l-lfishows a: resilient gripper element 21 :of-thegsame .generahstructure-.asrepresented in Figs. 9 @to l0. Inl' this instance however, thegvtlorkpiece irl-drawing properties of the form of 1 resilient gripper element shown `iny fEigs.-. v6 :to Stare ,achieved by cutting offrearwardparts ofthe respective outer and intermediate plies 35 and=35awinnthe staggeredzunmasking arrangement shown. Inother-words,

ithe-arrangementis such thatfworkpiece-.contact .face` 26 v.of rthel forwardlylocated .outermost ply 35 is shorterfthan the,l corresponding faces of the intermediatey andinncr- .fmost-` plies Y35a land A3512, respectively. l As ayresult of .this forma-tion, resilient gripper element :21zwill vbe-fprogressively'thinnergand thus ymore yieldable along .its-under facevfro-m front nose. 27 rearwardin order .toiexertthe :desired in-drawing pull on a workpiece Yengaged therewith in use of the implement on which said element. is

mounted.

-the outer margin of jaw D outside broken line y38, which outlines the original outermargin of the conventional jaw. Rib 37 is drilled to accommodate the .attachingscrews 32-32 of mountingmember 28,-twhich in this instance is ofsubstantially the same lengthv as resilient grippertclement 21.

Figs. 15 to 17, inclusive, disclosea-'still furthergformfof the resilient gripper element in which resilient changes in surface configuration Iis achieved almost exclusively by a metallic spring structure. A at arcuately bent spring mounting member 28 is shaped preferably to conform substantially to the curvature of the outer marginal edge of handle A and cutting jaw D and has a depending medial perforated ear 39 for penetration by pivot pin C. The rear end of member 28 is anchored to handle A in rear of the pivot by screw 4). At the front end of mounting member 28 in close proximity to nose d of jaw D, an extension of said member 28 is bent reversely inward to provide a straight resiliently compressible gripper element 21 in the form illustrated wherein its nose 27 projects beneath cutting edge d of jaw D and the free rear end portion thereof is inclined upward and rearward in converging relation to said cutting edge d to merge therewith at a point remote from nose d. The resilient gripperelement-forming extension of mounting member 28 preferably is inserted into a transversely stretched piece of small-diameter rubber tubing 41 in order to soften the workpiece-contact face 26 and also increase the friction of engagement with workpiece W. Fig. 16 depicts the manner in which resilient gripper element 21 flexes when pressed into engagement with workpiece W. The free end portion of resilient gripper element 21 is more exible than the nose portion 27, so the desired walling-in and in-drawing effects will be applied to the workpiece.

The rubber, or rubber substitute, used in production of the resilient gripper element and in facing the rigid gripper element, when this is done, should be carefully seleoted for degree of softness or flexibility. It should be suiciently exible to compress above and around a twig, vine, or other workpiece being cut without greatly increasing the pressure required to operate the implement handles but should be rrn enough to insure a secure grip on the severed workpiece. In other words, the rubber gripper element should be self-fitting and firm in its grasp regardless of the shape or size of the workpiece.

While it has been stated hereinbefore that the contemplated practice in modernization of existing models of pruning shears is to make available on the market sets of gripper elements and mounting means so that individual owners may do the work in their home workshops, it may be found to be more satisfactory for the manufacturer of the workpiece-holding accessory parts to do the job upon submission of the old models by their owners.

It will be understood that it is rintended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of illustration which do not constitute departures from the spirit and scope of the invention.

Having thus described the invention, I claim:

1. Workpiece-holding and indrawing pruning shears comprising: a pair of articulated handles united by pivotal means; coacting workpiece-severing jaws operatively supported by said handles; and workpiece-gripping means also supported in cooperative relation to the respective jaws and including a rigid gripper element immovable with respect to one of said jaws and a resilient gripper element movable with the other jaw in yielding relation thereto and positioned directly opposite to said rigid gripper element for contact therewith when the jaws are closed, said gripper elements having normally substantially straight opposed workpiece-contact faces of which the said face of the resilient gripper element is angularly arranged on lthe corresponding jaw with its forward portion more remote from the handle pivotal means projecting inward from 4said jaw into the mouth of the space between jaws when open to form a workpiece restraining nose and the rearward portion of said workpiece-contact face converging upon the rearward portion of said jaw, the composition and construction of the resilient gripper element being such that its nose is comparatively stiff and the portion rearward of said nose is increasingly more compressibly yielding with distance from the nose,

'whereby a workpiece initially restrained by the nose of the resilient gripper element 4in cooperation with the rigid gripper element will be drawn rearwardly inward along the said rigid element during closing action of the workpiece-severing jaws due to progressive rearward declination of resistance to compressive forces by said resilient gripper element.

2. Workpiece-holding and indrawing pruning shears as defined in claim 1, wherein the resilient gripper element is in the form of a block of rubberlike material that has yits inner workpiece-contact face inclined rearward in converging relation to the corresponding workpiece-severing jaw rearwardly from the mouth of the space between jaws.

3. Workpiece-holding pruning shears as defined in claim 1, wherein the resilient gripper element is in the form of a metalli-c spring having a base portion anchored to one of the handles and arranged to extent forwardly along the corresponding jaw to a point adjacent to the mouth of the space between jaws is bent rearwardly into a nose projecting inwardly beyond the inner workpiece-engaging face of said jaw and has a substantially straight free end portion extending rearwardly in normal rearwardly converging angular relation to said jaw, whereby the free end portion of the spring is progressively more yieldable as it recedes from the jaws mouth.

4. workpiece-holding pruning shears as defined in claim 1, wherein the resilient gripper element is a narrow block of soft rubberlike material mounted with one edge inwardly presented to form a workpiece-contact face, said block being laminated in formation and composed of innermost, intermediate and outermost plies, said outermost and intermediate plies having rearward portions thereof cut away in staggered relation whereby the forward portion of the block is comparatively thick and unyielding and the rear portion is progressively more yielding to exert an in-drawing eifect on a workpiece engaged by said block.

References Cited in the le of this patent UNITED STATES PATENTS 129,946 Grover July 30, 1872 257,389 Sager May 2, 1882 406,524 Jennings July 9, 1889 594,072 Forde Nov. 23, 1897 1,901,739 Engel Mar. 14, 1933 2,302,810 Steegmuller Nov. 24, 1942 FOREIGN PATENTS 148,648 France Apr. 28, 1882 10,064 Great Britain May 21, 1895 19,131 Great Britain Sept. 5, 1904 

